Custom reloptions for table AM

Let table AM define custom reloptions for its tables. This allows specifying
AM-specific parameters by the WITH clause when creating a table.

The reloptions, which could be used outside of table AM, are now extracted
into the CommonRdOptions data structure.  These options could be by decision
of table AM directly specified by a user or calculated in some way.

The new test module test_tam_options evaluates the ability to set up custom
reloptions and calculate fields of CommonRdOptions on their base.

The code may use some parts from prior work by Hao Wu.

Discussion: https://postgr.es/m/CAPpHfdurb9ycV8udYqM%3Do0sPS66PJ4RCBM1g-bBpvzUfogY0EA%40mail.gmail.com
Discussion: https://postgr.es/m/AMUA1wBBBxfc3tKRLLdU64rb.1.1683276279979.Hmail.wuhao%40hashdata.cn
Reviewed-by: Reviewed-by: Pavel Borisov, Matthias van de Meent, Jess Davis

10 files changed, 205 insertions, 0 deletions

diff --git a/src/test/modules/Makefile b/src/test/modules/Makefile
index 256799f520a..8f661525399 100644
--- a/src/test/modules/Makefile
+++ b/src/test/modules/Makefile
@@ -36,6 +36,7 @@ SUBDIRS = \
 		  test_rls_hooks \
 		  test_shm_mq \
 		  test_slru \
+		  test_tam_options \
 		  test_tidstore \
 		  unsafe_tests \
 		  worker_spi \
diff --git a/src/test/modules/meson.build b/src/test/modules/meson.build
index d8fe059d236..235e342dfaa 100644
--- a/src/test/modules/meson.build
+++ b/src/test/modules/meson.build
@@ -35,6 +35,7 @@ subdir('test_resowner')
 subdir('test_rls_hooks')
 subdir('test_shm_mq')
 subdir('test_slru')
+subdir('test_tam_options')
 subdir('test_tidstore')
 subdir('unsafe_tests')
 subdir('worker_spi')
diff --git a/src/test/modules/test_tam_options/.gitignore b/src/test/modules/test_tam_options/.gitignore
new file mode 100644
index 00000000000..5dcb3ff9723
--- /dev/null
+++ b/src/test/modules/test_tam_options/.gitignore
@@ -0,0 +1,4 @@
+# Generated subdirectories
+/log/
+/results/
+/tmp_check/
diff --git a/src/test/modules/test_tam_options/Makefile b/src/test/modules/test_tam_options/Makefile
new file mode 100644
index 00000000000..bd6d4599a14
--- /dev/null
+++ b/src/test/modules/test_tam_options/Makefile
@@ -0,0 +1,23 @@
+# src/test/modules/test_tam_options/Makefile
+
+MODULE_big = test_tam_options
+OBJS = \
+	$(WIN32RES) \
+	test_tam_options.o
+PGFILEDESC = "test_tam_options - test code for table access method reloptions"
+
+EXTENSION = test_tam_options
+DATA = test_tam_options--1.0.sql
+
+REGRESS = test_tam_options
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = src/test/modules/test_tam_options
+top_builddir = ../../../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
diff --git a/src/test/modules/test_tam_options/expected/test_tam_options.out b/src/test/modules/test_tam_options/expected/test_tam_options.out
new file mode 100644
index 00000000000..c921afcb270
--- /dev/null
+++ b/src/test/modules/test_tam_options/expected/test_tam_options.out
@@ -0,0 +1,36 @@
+CREATE EXTENSION test_tam_options;
+-- encourage use of parallel plans
+SET parallel_setup_cost = 0;
+SET parallel_tuple_cost = 0;
+SET min_parallel_table_scan_size = 0;
+SET max_parallel_workers_per_gather = 4;
+CREATE TABLE test (i int) USING heap_alter_options;
+INSERT INTO test SELECT i FROM generate_series(1, 10000) i;
+VACUUM ANALYZE test;
+EXPLAIN (costs off)
+SELECT * FROM test;
+           QUERY PLAN            
+---------------------------------
+ Gather
+   Workers Planned: 4
+   ->  Parallel Seq Scan on test
+(3 rows)
+
+ALTER TABLE test SET (enable_parallel = OFF);
+EXPLAIN (costs off)
+SELECT * FROM test;
+    QUERY PLAN    
+------------------
+ Seq Scan on test
+(1 row)
+
+ALTER TABLE test SET (enable_parallel = ON);
+EXPLAIN (costs off)
+SELECT * FROM test;
+           QUERY PLAN            
+---------------------------------
+ Gather
+   Workers Planned: 4
+   ->  Parallel Seq Scan on test
+(3 rows)
+
diff --git a/src/test/modules/test_tam_options/meson.build b/src/test/modules/test_tam_options/meson.build
new file mode 100644
index 00000000000..d41a32a6803
--- /dev/null
+++ b/src/test/modules/test_tam_options/meson.build
@@ -0,0 +1,33 @@
+# Copyright (c) 2024, PostgreSQL Global Development Group
+
+test_tam_options_sources = files(
+  'test_tam_options.c',
+)
+
+if host_system == 'windows'
+  test_tam_options_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
+    '--NAME', 'test_tam_options',
+    '--FILEDESC', 'test_tam_options -  test code for table access method reloptions',])
+endif
+
+test_tam_options = shared_module('test_tam_options',
+  test_tam_options_sources,
+  kwargs: pg_test_mod_args,
+)
+test_install_libs += test_tam_options
+
+test_install_data += files(
+  'test_tam_options.control',
+  'test_tam_options--1.0.sql',
+)
+
+tests += {
+  'name': 'test_tam_options',
+  'sd': meson.current_source_dir(),
+  'bd': meson.current_build_dir(),
+  'regress': {
+    'sql': [
+      'test_tam_options',
+    ],
+  },
+}
diff --git a/src/test/modules/test_tam_options/sql/test_tam_options.sql b/src/test/modules/test_tam_options/sql/test_tam_options.sql
new file mode 100644
index 00000000000..4f975046568
--- /dev/null
+++ b/src/test/modules/test_tam_options/sql/test_tam_options.sql
@@ -0,0 +1,25 @@
+CREATE EXTENSION test_tam_options;
+
+-- encourage use of parallel plans
+SET parallel_setup_cost = 0;
+SET parallel_tuple_cost = 0;
+SET min_parallel_table_scan_size = 0;
+SET max_parallel_workers_per_gather = 4;
+
+CREATE TABLE test (i int) USING heap_alter_options;
+
+INSERT INTO test SELECT i FROM generate_series(1, 10000) i;
+VACUUM ANALYZE test;
+
+EXPLAIN (costs off)
+SELECT * FROM test;
+
+ALTER TABLE test SET (enable_parallel = OFF);
+
+EXPLAIN (costs off)
+SELECT * FROM test;
+
+ALTER TABLE test SET (enable_parallel = ON);
+
+EXPLAIN (costs off)
+SELECT * FROM test;
diff --git a/src/test/modules/test_tam_options/test_tam_options--1.0.sql b/src/test/modules/test_tam_options/test_tam_options--1.0.sql
new file mode 100644
index 00000000000..07569f7b5f1
--- /dev/null
+++ b/src/test/modules/test_tam_options/test_tam_options--1.0.sql
@@ -0,0 +1,12 @@
+/* src/test/modules/test_tam_options/test_tam_options--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_tam_options" to load this file. \quit
+
+CREATE FUNCTION heap_alter_options_tam_handler(internal)
+RETURNS table_am_handler
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT;
+
+CREATE ACCESS METHOD heap_alter_options TYPE TABLE
+HANDLER heap_alter_options_tam_handler;
diff --git a/src/test/modules/test_tam_options/test_tam_options.c b/src/test/modules/test_tam_options/test_tam_options.c
new file mode 100644
index 00000000000..13e227e85b5
--- /dev/null
+++ b/src/test/modules/test_tam_options/test_tam_options.c
@@ -0,0 +1,66 @@
+/*--------------------------------------------------------------------------
+ *
+ * test_tam_options.c
+ *		Test code for table access method reloptions.
+ *
+ * Copyright (c) 2024, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ *		src/test/modules/test_tam_options/test_tam_options.c
+ *
+ * -------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "access/reloptions.h"
+#include "access/tableam.h"
+
+PG_MODULE_MAGIC;
+
+PG_FUNCTION_INFO_V1(heap_alter_options_tam_handler);
+
+/* An alternative relation options for heap */
+typedef struct
+{
+	int32		vl_len_;		/* varlena header (do not touch directly!) */
+	bool		enable_parallel;	/* enable parallel scans? */
+} HeapAlterRdOptions;
+
+static bytea *
+heap_alter_reloptions(char relkind, Datum reloptions,
+					  CommonRdOptions *common, bool validate)
+{
+	local_relopts relopts;
+	HeapAlterRdOptions *result;
+
+	Assert(relkind == RELKIND_RELATION ||
+		   relkind == RELKIND_TOASTVALUE ||
+		   relkind == RELKIND_MATVIEW);
+
+	init_local_reloptions(&relopts, sizeof(HeapAlterRdOptions));
+	add_local_bool_reloption(&relopts, "enable_parallel",
+							 "enable parallel scan", true,
+							 offsetof(HeapAlterRdOptions, enable_parallel));
+
+	result = (HeapAlterRdOptions *) build_local_reloptions(&relopts,
+														   reloptions,
+														   validate);
+
+	if (result != NULL && common != NULL)
+	{
+		common->parallel_workers = result->enable_parallel ? -1 : 0;
+	}
+
+	return (bytea *) result;
+}
+
+Datum
+heap_alter_options_tam_handler(PG_FUNCTION_ARGS)
+{
+	static TableAmRoutine tam_routine;
+
+	tam_routine = *GetHeapamTableAmRoutine();
+	tam_routine.reloptions = heap_alter_reloptions;
+
+	PG_RETURN_POINTER(&tam_routine);
+}
diff --git a/src/test/modules/test_tam_options/test_tam_options.control b/src/test/modules/test_tam_options/test_tam_options.control
new file mode 100644
index 00000000000..dd6682edcdf
--- /dev/null
+++ b/src/test/modules/test_tam_options/test_tam_options.control
@@ -0,0 +1,4 @@
+comment = 'Test code for table access method reloptions'
+default_version = '1.0'
+module_pathname = '$libdir/test_tam_options'
+relocatable = true